Refractometer

[MT_is_a_Pisces]

What would cause two different brands of refractometers both calibrated with RO water to have different readings, then different readings with calibration fluid ?

 

[LAReefer4Life]

How much of a discrepancy between the 2? What brands do you own? Possibly faulty product.

 

[SPR1968]

Well I have the Red Sea , the D D and Apex and they all read slightly different so I guess there must be a certain margin of error and they can be very sensitive especially the Red Sea one

I have always used the Red Sea as primarily so calibrate Apex to match this.

Consistency is the key, so pick one and stick with it.

 

[LAReefer4Life]

I agree with margin of error comment. I have the apex and Red Sea refractometer and there is always a slight measurable difference.

 

[bluprntguy]

Refractometers are finicky little pieces of equipment. I’ve had three of them and they would all give different readings immediately after calibration using the EXACT SAME calibration fluid. I found that they are all highly dependent on how hard you press the plate in place. This is the reason I switched to the Hanna salinity checker when I started up my latest tank.